How many worlds are there? You're reading this news article in one—let's call it the brick and mortar world. But we are surrounded by a growing number of virtual worlds in which people live, play, socialize, have jobs, earn a living, build homes, and occasionally bonk each other on the head with clubs. The threads of crypto-currency, non-fungible tokens (NFTs), social experiences through apps on smartphones, and ever-better immersive technologies that include 3D headsets and haptic technology, are being woven together. Virtual worlds that many still categorize too narrowly as "games" are emerging. Today, some people spend more time living in those virtual worlds than they do in this brick and mortar one.